Endometriosis is a commonly encountered gynecologic disease requiring medical or surgical therapy. As many as 6 to 10% of women of reproductive age are considered affected by this disease (Houston, 1984; Sensky and Liu, 1980). Although endometriosis can appear benign and its symptoms usually disappear in post-menopausal women, resultant infertility and severe, disabling pain significantly diminish patients' quality of life (Farquhar, 2000; Murphy, 2002). In developing countries the number of endometriosis patients is increasing (Bruner-Tran et al., 1999; Osteen and Sierra-Rivera, 1997; Rier and Foster, 2002; Rier, 2002).
Endometriosis occurs only in higher primates, including humans and baboons. Spontaneous endometriosis reportedly occurs in about 25% of captive baboons, and its prevalence increases with captivity duration (D'Hooghe, 1997). Experiments in non-human primates show a clear positive correlation between endometriosis and a diet containing the chemical dioxin (Rier et al., 1993; Rier et al., 2001), which may promote endometriosis by acting as an estrogen-like factor. In patients with endometriosis, many of the pathologic processes including inflammation, the immune response, angiogenesis and apoptosis are all favored for promoting endometriosis in a manner dependent on steroid hormones (Giudice and Kao, 2004; Osteen and Sierra-Rivera, 1997). Thus, in the past most treatment was via therapeutics targeting steroid hormones and their receptors (Hayes and Rock, 2002; Olive and Pritts, 2001). These drugs can only be administered for a short term due to side effects. Current first-line therapy is oral contraceptive pills (OCPs), which halt an ovulation and suppress endometriosis tissue growth with minimum side effects (Amsterdam et al., 2005). OCPs are also administered with nonsteroidal anti-inflammatory drugs (NSAIDs), further reducing endometriosis-associated pain (Johnson and Farquhar, 2006; Vercellini et al., 2003). Nonetheless these treatments do not remove endometriosis, and patients with severe symptoms must undergo surgery. However, even then symptoms can recur, requiring multiple surgeries in many cases (Vercellini et al., 2009). Thus it is critical to develop new strategies to cure this disease.